Add more components to GN build.

components/favicon/core/BUILD.gn

Index: components/favicon/core/BUILD.gn
diff --git a/components/favicon/core/BUILD.gn b/components/favicon/core/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..0f834cb1d8538adcac7c91f4c4ab32260d29539e
--- /dev/null
+++ b/components/favicon/core/BUILD.gn
@@ -0,0 +1,18 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+static_library("core") {
+  sources = [
+    "browser/favicon_client.h",
+    "favicon_driver.h",
+    "favicon_url.cc",
+    "favicon_url.h",
+  ]
+
+  deps = [
+    "//components/favicon_base",
+    "//components/keyed_service/core",
+    "//ui/gfx/geometry",
+  ]
+}